;
;  CALLING SEQUENCE:  radius=it_getrad(header)
;
;  PARAMETERS:	radius is the containment variable for the number found
;		in the header, header is the fits header.
;
;  NOTES:	I wrote this function because it seems every dataset had a
;		different keyword for the solar radius in their header, so I
;		wrote a function that will look in the header and find the
;		radius no matter what dataset I'm using.  This way, I only
;		have to keep updating this function for each new dataset
;		encountered.
;
;		(Gives solar radius in pixels.)
;
;  RETURN TYPE: float
;
;  CALLS:	FXPAR.PRO
;
;  HISTORY:	Drafted by Tony Darnell, 27-MAR-97
;		4-APR-97:  	Added MLSO/ACOS dataset test to calculate
;				solar radius from RSUN and CDELT1 parameters.
;
;		2007-7-9 sitongia: added STEREO SECCHI
;

FUNCTION it_getrad,header

  ;---STEREO SECCHI Dataset
  temp=fxpar(header,'OBSRVTRY')
  temp_err=!err
  IF (temp_err NE -1) THEN BEGIN
    rsun=fxpar(header,'RSUN')
    div=fxpar(header,'CDELT1')
    radius=rsun/div
    RETURN,radius
   ENDIF
  ;---MLSO MKIII dataset
  temp=fxpar(header,'CRRADIUS')
  rad_err=!err
  IF (rad_err NE -1) THEN BEGIN
    radius=temp
    RETURN,radius
  ENDIF	

  ;---MLSO/ACOS Dataset
  test=fxpar(header,'OBJECT')
  test_err=!err
  IF (test_err NE -1) THEN BEGIN  ;{
  IF (test EQ 'DPM SOLAR LIMB IMAGE: H-ALPHA') THEN BEGIN
  temp=fxpar(header,'RSUN')
  rad_err=!err
  IF (rad_err NE -1) THEN BEGIN
    div=fxpar(header,'CDELT1')
    radius=temp/div
    RETURN,radius
  ENDIF	
  ENDIF $
  ELSE IF (test EQ 'DPM SOLAR DISC IMAGE: H-ALPHA') THEN BEGIN
  temp=fxpar(header,'RSUN')
  rad_err=!err
  IF (rad_err NE -1) THEN BEGIN
    div=fxpar(header,'CDELT1')
    radius=temp/div
    RETURN,radius
  ENDIF	
  ENDIF
  ENDIF  ;}

  ;---LASCO Dataset
  temp=fxpar(header,'INSTRUME')
  temp_err=!err
  IF (temp_err NE -1) THEN $
  IF (fxpar(header,'INSTRUME') EQ 'LASCO   ') THEN BEGIN
    date=fxpar(header,'DATE-OBS')
    time=fxpar(header,'TIME-OBS')
    pltscl=fxpar(header,'PLATESCL')
    angle=pb0r(date+' '+time,/arcsec)
    radius=angle(2)/pltscl
    RETURN,radius
  ENDIF

  ;---YOHKOH dataset
  temp=fxpar(header,'RADIUS') 
  rad_err=!err
  IF (rad_err NE -1) THEN BEGIN
    radius=temp
    RETURN,radius
  ENDIF					$
  ELSE  				$

  ;---EIT dataset
  temp=fxpar(header,'SOLAR_R')
  rad_err=!err
  IF (rad_err NE -1) THEN BEGIN
    radius=temp
    RETURN,radius
  ENDIF					$
  ELSE					$

  ;---Radio dataset
  temp=fxpar(header,'SOLR')
  rad_err=!ERR
  IF (rad_err NE -1) THEN BEGIN
    cdelt=fxpar(header,'CDELT1')
    radius=temp/cdelt
    RETURN,radius
  ENDIF					$
  ELSE					$

  ;---BBSO Dataset
  temp=fxpar(header,'WIDT')
  rad_err=!ERR
  IF (rad_err NE -1) THEN BEGIN
    width=fxpar(header,'WIDT')
    radius=width/2
    RETURN, radius
  ENDIF					$
  ELSE					$
  radius=-999999.00

  RETURN,radius
END